Remote monitoring and control of Substation Automation systems (SAS), and protection, monitoring and controlling devices has taken many forms. In the past, dedicated lines were the common form of communication between a control system and a remote location. This type of communication had limited application since the control system was not accessible from multiple locations. Modems have made it possible to access the control system from different locations, but this type of access required implementing generally specific communication protocols. Providing any type of control function between locations is rather limited in this type of environment. Furthermore, a customized interface is generally required to access the control system by an end user.
With the growth of Internet and its World Wide Web providing a delivery platform for organizing Internet data through hypertext links, a client server system can be designed that will give each end user the same type of user friendly interface and universal access to services on the Web. The Web is a network of documents called sites or pages stored on server computers throughout the world. Each page typically contains text, multimedia offerings, i.e., graphic images, video, or audio; and hypertext links to other Web pages or documents. A browser allows a user to read and interact with the Web page. The browser is a graphical software program that sends commands to the Internet Web site and displays whatever information is available on the page. As is well known, various browser programs are commercially available from different manufacturers.
The Internet network employs methods designed to handle many general-purpose computers sharing a single cable, and therefore has no ability to differentiate traffic in terms of its purpose or the criticality of its data. The Internet is no longer a network of computers sharing a single cable, but rather a web of interconnected point to point links involving both general purpose stations and specialized infrastructure components such as routers and firewalls.
Most personal computers or work stations can be used by the end user to connect to the Web through the commercially available browsers. Communication over the Internet and other networks requires one or several available protocols. Protocols such as Internet Protocol (IP) provide for file transfers, electronic mail, and other services. Commercially available programming languages such as Java or ActiveX, along with Hypertext Markup Language (HTML) and Extensive Markup Language (XML), are used in designing layouts and graphics for a Web site or page and have extended Internet technology such that a Web site can be used for dynamic applications, e.g., applets or plug ins, that can be downloaded and run by the end user.
Many manufacturers provide automation information using dedicated hardware and software with private communication networking environments. Numerical protection units, electronic meters, fault detectors, substation control units and Remote Terminal Units (RTU) are widely used in control network systems. In addition to these devices, monitoring and controlling modules for smart power equipment (e.g. intelligent circuit breaker, switch gear and power transformer) may also be integrated in process control systems. Such specialized environments can be very expensive. Furthermore, these systems are based on proprietary communications busses and conversion products are required to allow information carried over those networks to be visible on a general-purpose network. There are significant installation and other deployment costs associated with the existence of such intermediate devices.
It would be desirable to develop an electrical network control system whereby a user could use general purpose communication networks, such as the Internet and specialized industrial networks, directly connected to intelligent power equipment, protection units, electronic meters, fault detectors, substation control units and RTUs for remote monitoring and control access.
This invention is designed to solve these and other problems.